I think the phrase
They also pass European laws and many Countries' Laws for maximum allowed Watts because the motor is not attached to the bike frame or wheels of the bicycle.
is a bit optimistic, and possibly downright misleading.
In the UK, if it's not covered by the Electrical Bicycle regs, then it's not a bicycle, it's a motor vehicle, and it'll only be legal if you've got things like type certification, MOT, VED, Insurance, a driving licence and so forth (most of which would be impossible with this setup).
Now, it's highly unlikely you'd get stopped and be prosecuted, but suggesting that this is a public road legal arrangement is almost certainly wrong.